Mass termination, insulation displacement connectors have come into increasing commercial prominence because of the significant savings in time and labor they offer compared to stripping and individually terminating each conductor using a crimp terminal. These connectors have an insulative housing body holding a number of regularly spaced terminal elements having slotted plates terminating in sharpened free ends extending beyond a surface of the body. The connectors also include covers having recesses in a facing surface for receiving the free ends of the plates. After the insulated conductors are aligned with their corresponding slotted plates, relative closing of the housing body and cover results in displacement of the insulation with the conductor cores contacting the metallic plates. For further information regarding the operation and structure of such mass termination connectors, reference may be made to U.S. Pat. Nos. 4,458,967 and 3,912,354.
The most efficient form of conductors for use with such connectors is the flat cable in which conductors, running parallel and spaced to match the spacing of the terminal elements in the connector, are held by a layer of insulation. The use of a flat cable avoids running the conductors one at a time and holding them in position for termination. The flat cable can be used for either a daisy chain connection (where the connector is applied intermediate the cable ends) or an end connection. The sharpened ends of the slotted plates pierce the web material between the conductors in the flat cable as the body and cover close so slitting of the cable between conductors is not required.
While flat cables offer many advantages with respect to efficiency in termination, they present difficulties during routing. Flat cables have certain dimensions larger than comparable round cables, the flat cables do not bend as easily, they are more susceptible to damage during routing, and the continuous presence of the layer of insulation holding the discrete conductors may result in somewhat increased weight of a flat cable.
An electrical cable has been proposed including alternating flat cable and twisted pair sections with an outer jacket holding the cable so that it has a generally circular cross section to provide flexibility superior to that of a flat cable. The provision of the twisted pair sections reduce cross talk among conductors. This cable carries spaced indicia to mark the location of the flat cable sections to limit the extent that the outer jacket need be removed to prepare a flat cable section for termination. However, in the event of significant slippage between the outer jacket and the conductors, the markings could move out of alignment with the flat cable sections. For further information concerning the structure and operation of this cable, reference may be made to commonly-assigned U.S. Pat. No. 4,767,891.
U.S. Pat. No. 4,543,448 to Deurloo for ELECTRICAL CORD teaches a magnetically identifiable conductor, for use in a cord set. The cord set has insulated conductors, each having a conductive core. A conductive core 23, in addition to copper wires, has a single steel wire strand in order to identify it as a ground lead. The cable is rotated until the ground lead having the high magnetic permeability conductor therein is brought into proximity with a detector. Once it is detected, suitable connectors may be affixed to it and the manufacturer will know that connection has been made to the ground lead at both of its ends.
U.S. Pat. No. 1,906,820 to Shaw for MAGNETIC DETECTOR is directed to an apparatus for detecting small magnetic particulates in the insulating jacket of an electrical cable during manufacture. A magnetic detector is placed in proximity with the cable and controls a cable feeding mechanism. The system interrupts manufacture of the cable in the event that a steel bristle becomes entangled therein.
U.S. Pat. No. 1,944,954 for a FLAW DETECTOR FOR ELECTRICAL CONDUCTORS discloses a method of detecting flaws in an electrical cable when current is passed through it by sensing the magnetic field formed around the cable. Thus, the cable must be energized.
British Patent Specification No. 1,432,548 is directed to a method of printing indicia on a cable after which the cable is covered with a transparent sheath.